**Core Concept**
The question describes a clinical scenario of a patient with a large pelvic mass, characterized by bony destruction and calcifications, which is resected and has a bluish-white cut surface. This presentation is suggestive of a primary bone tumor, specifically a type of malignant neoplasm.

**Why the Correct Answer is Right**
The gross description of the mass with a bluish-white cut surface is a classic feature of **Chondrosarcoma**. This type of cancer arises from cartilaginous tissue and is known for its production of mucoid material, which gives it a bluish-white appearance. Chondrosarcomas often occur in the pelvis, long bones, or ribs, and are characterized by bony destruction and calcifications within the tumor.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as **Osteosarcoma** typically presents as a destructive bone lesion with a "sunburst" pattern of new bone formation, and does not usually have a bluish-white cut surface.
**Option B:** This option is incorrect as **Ewing's Sarcoma** is a highly malignant tumor that typically affects younger individuals and presents with a mixed lytic and sclerotic appearance on imaging, without a characteristic bluish-white cut surface.
**Option C:** This option is incorrect as **Lymphoma** can present as a pelvic mass, but typically does not have a bluish-white cut surface or extensive bony destruction with calcifications.

**Clinical Pearl / High-Yield Fact**
Chondrosarcomas are often difficult to distinguish from benign cartilaginous tumors, such as enchondromas, on radiologic examination alone. A key distinguishing feature is the presence of bony destruction and calcifications within the tumor, which suggests a malignant process.

**Correct Answer:** C. Chondrosarcoma.